Grid leak



May Z5 1926. 1,586,457

L, J. MoNcRlEF GRID LEAK Filed OCT.. 3l, 1923 INVENTOR ATTORNEY wrrNEss:

Patented May 25, 1926.

UNITED S'Iffl LAWRENCE zr. Moncnrnr, or WINFIELD, KANSAS.

GRID LEAK.

Application filed October 31, 1923. Serial No. 671,977.

This invention relates to improvements in grid leaks for wireless apparatus.

An object of the present invention is the provision of a grid leak of simple construction, which may be connected directly with any of the terminals v'of a vacuum tube, so as to provide simple and convenient means for connecting the leak in an out-of-the-way position and at the same time provide a leak which may be connected in the circuit in the usual manner.

lVith the above and other objects in View, the invention further includes the following novel features and details of construction, to be hereinafter more fully described illus trated in the accompanying drawings and pointed out in the appended claims.

'In the drawings rFigure 1 is a bottom plan view of la vacuum tube with the leak in position.

Figure 2 is a similar view showing the leak engaged with different terminals of the tube.

Figure 3 is a plan view Vof the `grid leak looking at the side opposite that. shown in Figures 1 and 2.

Figure 4 is an edge view of the grid leak.

Figure 5 is a section on the line 5 5 of Figure 3.

Figure 6 is a section on the line .6--6 of Figure 3. f

Figure 7 is a detail view of one of the binding strips. i.

Figure 8 is a plan view of a modified Vform of the invention.

Referring to the drawings in detail wherein like characters of reference denote corresponding parts, the reference character V indicates a vacuum tube whose plate terminal is indicated at P, grid terminal at G and filament terminals at F and F, one being the positive and the other the negative filament terminal.

The grid leak which is indicated generally at L comprises a base 10 which is formed of some suitable insulating material such as bakelite. This base is provided with openings 11 and 12, the latter being relatively large. The base is further provided at one end with a notch 13 which is in alignment with the openings.

Mounted upon the base between the openings 11 and 12 is a strip of high resistance material 14, the said strip being held in place by means of copper binding strips 15. These strips 15 extend transversely across the base over lthe ends of the resistance material 14 and are provided with openings 1.6 for register with the openings 11 and 12 of the base. In order to provide openings upon opposite sides of the base, the ends'of the strips are provided with semi-circular notches 17 so as to form proper size openings when the strips are in position.

@ver the meeting ends of the strips 15 there is placed a plate 18 of insulating material which is of the same shape and size as the base 10 and which may be secured to the base by means of shellac or other adhesive material. If desired a sheet of mica 19 may be placed over the resistance material 14 for the protection of the latter. The base 10 and the plate 18 are relatively thin, the said plate 18 which may also be formed of bakelite or other insulating material, may be thinner than the base 1() as it merely forms a cover for the resistance material 14.

Secured to the strips 15 by means of hollow rivets 20 are spring contact members 21 and 22. These members may be of any suitable type, but it is preferred to form them of spring brass shaped to provide rings 23 which surround the openings 16, while -projecting from these rings rare fingers which are bent to provide the spring contact members 21 and 22 previously mentioned. The finger which forms the contact member 22 may be relatively long and shaped so as to extend over both the opening 11 and the notch 13.

The grid leak constructed in the manner just Ydescribed may be engaged over the tube terminal G and the tube terminal F as shown yin Figure 1 so that the said terminals will engage the spring contacts 21 and 22. If desired, the leak may be engaged over the tube terminal G and the tube terminal F as shown in Figure 2. It will thus be possible to connect the grid, through the leak, to

veither terminal ofvan A battery so as to place either a positive or a negative charge upon the grid. The opening 12-is of greater diameter than the opening 11 so as to adapt the leak to different tubes in which the distance between the terminals may slightly vary.

The form of the invention shown in Figure 8 is substantially the same as that just described except that the cover plate 18 is omitted and the high resistance is formed in separate sections 23 and 24. These sections are spaced apart and may be eleetricallyv connected by any desired means such as by means oit an ordinary Jencil line 25, the thickness of which may vary to provide a variable leali.

The invention is susceptible ot various changes in its term, proportions and ininor details et construction and the right is herein reserved to malre such changes as properly tall within the scope ot the appended claims.

Having described the invention what is claimed is l. A grid leali comprising a base toi-ined of insulating material, means whereby the base may be reniovably engaged over the terminals el" ay vacuum tube, a resistance element carried by the base and means wl eroby the resiietanee element n f be electrically connected to the tube terminals.

2. A grid leal; conprising a bise i'ormed ot insulating material, means .vhereln/ the base may be engaged with the tern'unals oit a vacuum tube, a resistance element carried by the base and yieldable contact members electrically connected to the resistance ele-- mentI :tor engagement with the tube ternunals.

3. A grid leak comprising a base Ytermed oi insulating material, means the base may be removably e two terminals off a vacuum luce, a ressa, element carried by the base and me; is whereby the resistance element nxav be electrically connected to the tube terr" A grid leal; comprising a base termed of insulating material and novided with spaced openings tor receiving the termina-.ls 'ot' a vacuum tube, a resistance element carried by Ythe base and means whereby the resistance element may be electrically connected to the tube terminals.

5. A grid leak coix'iprising a base 'formed of insulating material and pr vided with spaced openings and notch in one end thereof lfor receiving the terminals oit a vacuum tube, a resistance element carried by the base and means whereby the resistance element may be electrically connected to the tube terminals.

6. A grid leak comprising a base toi-ined 'ot insulating material and provided with spaced openings t'or receiving the terminals et' a vacuum tube, a resistance element carried by the base and means including yieldable contact members ez-tending from the openings for engagement with the tube terminals, .vhereoy electrical connection may be established between the tube terminals and the resistance elenie 7. A grid leak comprising a base Jiormed ot insulating material and provided with spaced openings and a notch in one end lhereoie tor receiving the terminals of a vacuum tube, a resistance element carried by the hase and means including yieldable contact members extending over the openings andL notch, whereby electrical connection may be Vstablished between the tube terminals and the resistance clement.

8. The combination with a vacuum tube, of a grid leal: and means whereby the grid leak may be directly secured over the contact terminals ol iid tube.

The combi?, with a vacuum tube, of a grid leal; and means whereby the grid leal; may be removably secured over the terminals ot' said tube so that either positive or negative current may be placed upon the tube grid.

i The combination with a vacuum tube7 a t,rid leal: having spaced openings therein to receive the contact terminals ot a tube, one olf said openings being ot a relatively largo diameter to compenate for ditlfeirences ot snaclng between the Contact terminals 01"' di ferent tul ll. A grid leal; con priiirg a base formed ot, insulating material and provided with openings spaced to receive the contact terminals et a vacuum tube, a resistance element shaped to conformA to the shape ot the ba metallic bands surrmindinggj "he base and resistance elemeiit and engaging the latter to provide a conductor, said bands having openings therein registering with the openings of thel base and resist-anco element, an insulating plate engaging the bands adjacent the resistance element and also provided with openings, hollow rivets extending through the openings oit the base, resistance element, bands and plate to receive the Contact terminals ot a vacunnl tube and contact members extending trom the rivets tor engagement with said terminals.

ln testimony whereof l al'iix my signature.

LAVVRENGQE J. MONCRIEF. 

